Electromagnetic switch



July s. 1924. 1,500,800

E. R. CRICHOFF ET AL ELEGTROMGNETIC 'SWITCH Original Filed Jan. 2s, 1920 2 sheets-sheer 1 Eugene R. Cav'chof, Benq) mm \)V dong-0S,

'Oy 25M @QW Thn" Attovmey.

July s, 19,24. 1,500,800

CARCHOFF' ET AL ELECTROMAGHETIC SWITCH originar Filed Jan. 2s. 1920 2 sheets-sheer 2' lm/entovsl Eugene RCavchf-vff. Bem YnnWdoheS by e. ii

Patented July 8,1924.

UNITED STATES EUGENE R. CARICHQFF AND BEQ'JAMIN V. JGNES, OF

PATENT SCHEN'ECTADE, NE?? SIG-N035 TO GENERL :ELECTRIC COMYANY, A. CORPORA'Y'IG `GF NEW" Ybren.

ELECTRMAGNETIC S'WTCH.

original application nled January 26, 1920, Serial No. 354,039. i Renewed To all whom it may concern.:

Be it known that' we, EUGENE R. CARI- onoire and BENJAMIN il?. JONES, citizens of the United States, residing at Schenectady,

5 in the county ot Schenectady, State ot New York, have invented certain. new and useful Improvements in Electromagnetic Switches, of which the following is a specification.

Our invention relates to imprpvements in electromagnetic switches and in particular to switches having two windings for oontrolling switch member biased to one position, one of the windings effective to operate the switch to another position against its bias and the other winding for govern-` ing the return of the switch member to the bia-sed position. The first winding may be termed the piclreup winding and the other winding the drop-out winding. One of e @bjects of our invention is to provid@ switch of the character indicated in which the pick-up and Ldrop-out value may loe independently adjusted. This application is a. oivision of our former and co-pendingl application, Serial No. 354,030,

liled January Q6, i920, renewed Janna-ry 6, Serial llo. 527,520, in which we have fullyr disclosed our improved electromagnetic switch and have claimed an improved e system of control 'for electric motors in which this switch is employed.

in carrying our invention into effect, we provide a single switch member which is biased to one position and controlled by means or" a pick-np electroinagnet and a dropout electromagnet. -The elect-roma@ nets have substantially independent magnetic structures and improved means is provided whereby the magnetic reluctance ot the 'electromegnets may be independently adjusted or varied in order that the picup and drop-out values may be predetermined at will. ln one form of our invention, each elcctromagnet is provided with of each armature is adjustable with respect to the winding of its electromagnet independently of the armature for the other electromagnet.

For a better understanding 'oi' our invention, reference is had to the accompanying drawings, in which Fig. l is a side view of our improved electromagnetic switch; Fig. 9;

Divided and this application filed November 2, i920, Serial No. 421,291.

an armature or other movable member can" ried by the switchv member, and the position' annary 6,

is a plan'view ot the saine; Iig. 3 is a simplimotor control s I D lied .diagram of a system cir i.

repro v ,c ecemplo'ying a pluralitf,7 ot `oui i of contactors whichcontrol the .1 sistors of an electric motel;

Referring to Figs. and 2 of the drawings, our improved electromagnetic switch 2O comprises a stationary contact and a movable contact 25 Themovable Contact 25 is connected to the pivoted and movable member 2&3, to which the armature 2.7 of the upper coil 2S is connected and to which the armature 29 of the lower coil 30 is also connected. Contact is biased 'to the unattracted position, that in which the contacts 2de and 25 make engagement, by means of the spring` 31. ln this embodiment ot' our invention, the switch is shown as losing normally closed, but our invention is not limited thereto, will be explained in connection with the arrangement of F i. rlie armature 2"? is supported by a bolt having a screw thread whereby the armature may be vcr-v nicely adjusted with respect to thecore 3.25 of the electromagnet of which the 28 forms a part. A. friction member 3st having" a certain amount ot' resiliency is provided tor retaining the armature /L'l' in the position to which it has been moved. The lower armature Q9 is likewise mounted on bolt 35 having a screw thread and a resilient friction device 36 for holding the armature in the position to which it has been adjusted with respect to the core 3T of the electro-I 4magnet of which the winding 30 forms a resistors Ru, FB2 and R in the motor cro rlhe member 26 carrying the the ciosing ci the piiot switch *Z4 energizes cuit to limit the correct taken he motor in starting. The closing the switch 'TQ short circ'eits t}ie-pici-iip winding 7l oi the iist eiectromegnetic switch enti permits this switch to close its coritec-resgoonsi's'eqyy to the voitege drop across the resistor Rik fe dosing; ci the iirst eiectromegoetic l pickujo Winding @Ilich short circuits .2 of the second eiectromagnetic switch and jgs-ermite 'this switch to he closed respoiisiveiy to t e eiiergizetiori of the rooout Wind.- iiig 33 which is energized respoiisiveiy to 'the voitefre rop across the resistor R12.

i certain time iitervci Wiii 1ce introthiceri in the dosing of. the switch. reason of the fact that the pick-up eicctromegnet has s, certain attractive effect for en interval after its winding is short circuited vThis time iiiter/ei may he varied hy varying the positions of the armature on the boit 35, since the .'oeerer the armature to the core of the eieoticmegnet, the ioiiger the armatore Wiii ilse heid hy the ii'iegiietizstion after the coil is cieenergized. The closing of the second electromagnetic switch iiie causes the third electromagnetic switch to ciosein accordones With its hiasto the closed position responsiveiy to the Voitege drop across the resistor R13. The opening of the switch TG causes the opening of sii of the eiectromegizetic resistance switches, since the iower or pickup Winiiigs ere sii energized in muitigpie across the contacts of switaeh 70. The parts Wiii then he in the positions shown iii the drawing.

Ii? the arrangement of Fig. 4;, the eiectromegietic switches or ccntsctors which controi the starting resistors ,are of the normeiiy closed type, cod the electromagnetic rele-ys :for controiiing these starting contectoi's are ci the normeiiy open type. With the parts in ,the positions shown iii the figure,

the iine contacter 75 to ciose emi connect the rector to the source of supo j with the startieg resistors R12 Rlend :itis included in the motor circuits to iimit the current taken hy the motor starting'. The cio-sieg of the line conte'ctor75 short circuits the pic Windiiig T6 of the i'irst reey and ehergizes the drop-out winding of this reicy responsiveiy to the voltage drop across the resister R14. The Winding 78 of the second relay will be energized responsiveiy to the voitage cirop across the resistor R14, the winciing 79 wiii he energi eri in accorecce with the Voltage rcp across the resistor R15,

"the Winding 80 will be energized in scoordence with the voltage drop across the resister RL and R1, and the winding 5:53. 'siii he energized in tsccmcence with the vctege siropacross the resistor R1". 'it Wiii he coserve that with the mecueij/ opereteri Clif#- connecting switch 82 ciosefi 51nd the' iirie contaeter 75 operi, es shows the drawing, the

motors ere eppiieci.

reis-ys costroiiing the resistance coritactors are sii energized ro4 close their contacts against their biss the oper: position, esci t e resistance conte-tors are energmeii to en their conti-iets against their bias to the the resistor RM cmi the winding 73 ci' the c second, romy. The windings of the resistent: coiitoctors Si and 85 Wiii be deencrgizec i succession to short circuit the resistors R1 and-R16 in succession in a mailer which wiii be obvious to those siiiiied in the srt.

it wiii he observed that the magnetic structure ci each of the two eiectromegnets ci our improved electromagnetic switch is substanticiiy independent oi the other eiectromaghet, and that Flux path of each eLect-ro magnet may he varied indepenoientiy o the iux path of the other eiectromsgnet by verying the positions of the armatures with respect to the cores of the eiectromegnets. it wiii eiso he observed that the switch lJoey he either of the normeiiy open or the normeiiy ciosed type, depending 'upon Whether 'the movable switch contact 25 is adapted to com plete an electric circuit when the movable switch member 26 is in its biased position or tc interrupt a circuit when the switch member is in its biased position. ic other Words, the switch may be used to either interrupt en electric circuit when the pickup Winding is energized, or vto make s circuit when this Winding is energized. l

The velues at which the Essays Wiii open end ciose may he varied imiepenentiy of each other, and this wide range of permissihie edjistmeht makes the reicj; suitehie Jfor almost eli kinds of service to Whici eiectric it xviii also he noted that the same reiay enti coiis he used for of motors ci suostaiitieiiy the same mittags hereby eecting a. simpii's'icetion and reductioif: of ythe cost of controi equipments and necessitating the carrying' of very few spore parts in stocir. Since there are no interlocking-contacts, e greet many operating trouhies are eliminated, the Wiriiig is very simpie, aii less time arid f ebor wiii he required in haii-ing e contrci equipment. The retej/s have no mechanical connection with the resistance coiotoctors :wel hecioccted in any ciesirehe piece, or may ce ochec ro sway from unauthorcersons enti I from dirt. The conl J" L' L acct parte or the .i y reiticei and mii 'tires rotem miiiiiricm rif-nocht 2?? the seite? :s of the cioseci li-G 1,5oo,soo

type as shown in Fig. 3, called on to break a. circuit and thus may be made quite simple and inexpensive, since the closingl of a. circuit is relatively simple as comparedto breaking a circuit. especially an inductive circuit. Because of that. tact, the movement of Athe switch contacts may be anything desired, and the pick-up and dropout values of the switch may be adjusted without regard to the distance which sepa'- rates the contacts when the switch is open. Because ot the wide range of permissible adjustment,'either one of the switch coils `may be connected so as to assist in effecting the opening oit the switch or be connected as the coil which governs the closing of the switch. Since both switch coils are deenergized after the switch closes, there is no tendency to open the switch or to diminish the pressure on the switch contacts due to the increase in current when the resistance is cut out.

A still further important advantage of our invention is that (referring to Fig. 3) incase any one of the resistancev switches should heef/1e, it would aii'ect only that section of resistance and not cause the motor to be connected practically directly to the source. Thus, assume that the cont-act tips of the first switch are accidentally welded shut and the resist-or R is short circuited. The'second switch will have its coil 72 short circuited by the first switch, but the rush of current' will. be such that the voltage drop the switch is never across the resistor R12 will energize the coil 73 to open the contacts ot the second switch. The second switch will open in the usual way, but this switch will be maintained open until after the current has dropped to the predetermined value. After the second switch closes the third will close in the manner previously explained. The systems of motor control disclosed in Figs. 8 and 4 are broadly and specifically claimed in our said application, Serial No. 354,030, filed January 26, 1920, renewed January 6, 1922, Serial No. 527,520, of which the present application is a 'divisionl` for the purpose of obtaining patentprotection for the electromagnetic switch which is disclosed in Figs. l and 2 of the present application and which is employed in the systems as shown in Figs. 3 and 1i.

In accordance with the provisions ot the patent statutes,fwe have described the principle 'ofoperation of. our invention, together with the apparatus which we now consider to represent the best embodiment thereof; butwe desire to ,have it understood that the apparat-fas shown is only illustrative, and that the invention can be carried out, by other-"means Whatwe` claim as cure by llett-ers Sta-tes, ieg# new and desire te sel'atent of the. United the hielten i windine D l. The combination in an electromagnetic switch, of a switch member biased to one position, two electromagnets jointly controlling the switch member, one for operating the same to another position against its bias to the first position and the other for magnetically holding the same in. the other position and for governing its movement to its biased position, and means :for governing the reluctance of the flux path ot each electrfmagnet independently of the other electromagnet whereby the operations of the switch member from and to its biased position are i independently governed.

2. The combination in an electric switch, of a movable switch member biased to one position, two electromagnets jointly controlling the same, one for operating the switch member to another position against its lbias and the other for governing the operation of the same to 'the biased position, each electromagnet having a magnetic structure which is substantially independent of the other electromagnet and each magrnetic structure having a separate indepen ently adjustable member connected to the switch member.

3. The combination in an electric switch of a switch member, jointly controlling the saine, each electromagnet having an armature secured to the switch member and a magnetic structure substantially independent of the other electromagnet, and means for adjusting each armature independently et the other arma ture so as to vary the effect of one electromagnet independently of the other.

Il. The combination in an electric switch of a switch member biased to one position, two electromagnets for controlling L'l e saine, one for moving the switch member to other position against its bias and the other for governing the movement oit the switch member to its biased position, eac-h electromagnet having a substantially independent magnet structureand a separate armature secured to the switch member Jor contv il ling the same, and means whereby the cosition or' the armatures with respect to their corresponding magnet structures are inde pendently varied so that the movements of the switch member to and from the biased position are adjusted independently of each other.

5. The combination in an electric switch. oi a switch member biased to one position, apick-up electromagnet for controlling the movement ofY theswitch member to onother position against its biasand a dropout electromagnet governing the ment of the position, eacheleetromagnet having sub stantially f independent magnetic structure,

adapted to b i* circuit/ed .as give the ccmtrceL two electromagnets for.

switch member to its biased' Lamm@ the same 30 :1S to vary ik@ value of current in me Winding of che doput eecro- 10 'be pwmii-ed i0 Teuln the biased position. 'Witness Whereo, we have hereunto set sur han@ l f ay of Novemel N20.

TE Rfi-FF, 

